I-joist span calculator: how far can an I-joist span?
19 ft 3 in
clear span, 11 7/8 in TJI 210 at 16 in on center · 21 ft 1 in at 12 in · 18 ft 2 in at 19.2 in · 16 ft 11 in at 24 in · at L/480 and 10 psf dead, Weyerhaeuser TJ-4000
Run your own numbers
Enter it the way you measured it: 4.5, 4 1/2,
3/8 or 10' 6".
19 ft 3 in
clear span, 11 7/8 in TJI 210 at 16 in on center · 21 ft 1 in at 12 in · 18 ft 2 in at 19.2 in · 16 ft 11 in at 24 in
Source: Weyerhaeuser Trus Joist TJI Joist Specifier's Guide TJ-4000 (July 2025), Floor Span Tables, page 7, read October 31, 2026. Data sheet (PDF)
An 11 7/8 in TJI 210 I-joist at 16 inches on center spans up to 19 ft 3 in between supports at L/480, with 40 psf live and 10 psf dead load and a glued and nailed subfloor (Weyerhaeuser TJ-4000, July 2025).
A worked example
A 14 in TJI 360 at 19.2 in on center, under a 20 psf dead load at L/360 with the subfloor nailed and not glued, needs a clear span of 21 ft 10 in or less. The page 7 cell is 22-4, marked (1), less 6 in for nails without adhesive. Checked against a 21 ft 7 in room it clears by 3 in; with the subfloor glued it would clear by 9 in. The (1) means web stiffeners at an intermediate support shorter than 5 1/4 in if the joist runs continuous over it.
How far can an 11 7/8 I-joist span?
From 15 ft 9 in to 26 ft 1 in at L/480 and 10 psf dead load, by series and spacing: a TJI 110 at 24 in on center reaches 15 ft 9 in, a TJI 210 at 16 in 19 ft 3 in and a TJI 560 at 12 in 26 ft 1 in. At L/360 the same TJI 210 runs 21 ft 2 in.
How far can a 14 TJI span?
At 16 in on center, 40 psf live and 10 psf dead load at L/480: 20 ft 11 in in TJI 110, 21 ft 10 in in TJI 210, 22 ft 6 in in TJI 230 and 23 ft 8 in in TJI 360. Under a 20 psf dead load the TJI 110 drops to 19 ft 2 in.
How far can a TJI 560 span?
The TJI 560 is the heaviest series in the table, 4.0 to 4.5 lb per foot. At 12 in on center and L/480 it spans 26 ft 1 in at 11 7/8 in deep, 29 ft 6 in at 14 in and 32 ft 8 in at 16 in; at L/360 the 16 in reaches 36 ft 1 in, the longest span on page 7.
What else it is called
Also searched as an I-joist span chart or table, a TJI span chart, or a wood I joist span calculator. TJI is the Trus Joist brand of I-joist, made by Weyerhaeuser. L/480 holds the live load deflection to 1/480 of the span; L/360 is the one the guide marks as the minimum per code.
The full TJ-4000 floor span table
| Deflection · depth · TJI | 12 in o.c., 10 psf dead | 16 in o.c., 10 psf dead | 19.2 in o.c., 10 psf dead | 24 in o.c., 10 psf dead | 12 in o.c., 20 psf dead | 16 in o.c., 20 psf dead | 19.2 in o.c., 20 psf dead | 24 in o.c., 20 psf dead |
|---|---|---|---|---|---|---|---|---|
| L/480 · 9 1/2 in · TJI 110 | 16-11 | 15-6 | 14-7 | 13-7 | 16-11 | 15-6 | 14-3 | 12-9 |
| L/480 · 9 1/2 in · TJI 210 | 17-9 | 16-3 | 15-4 | 14-3 | 17-9 | 16-3 | 15-4 | 14-0 |
| L/480 · 9 1/2 in · TJI 230 | 18-3 | 16-8 | 15-9 | 14-8 | 18-3 | 16-8 | 15-9 | 14-8 |
| L/480 · 11 7/8 in · TJI 110 | 20-2 | 18-5 | 17-4 | 15-9 (1) | 20-2 | 17-8 | 16-1 (1) | 14-4 (1) |
| L/480 · 11 7/8 in · TJI 210 | 21-1 | 19-3 | 18-2 | 16-11 | 21-1 | 19-3 | 17-8 | 15-9 (1) |
| L/480 · 11 7/8 in · TJI 230 | 21-8 | 19-10 | 18-8 | 17-5 | 21-8 | 19-10 | 18-7 | 16-7 (1) |
| L/480 · 11 7/8 in · TJI 360 | 22-11 | 20-11 | 19-8 | 18-4 | 22-11 | 20-11 | 19-8 | 17-10 (1) |
| L/480 · 11 7/8 in · TJI 560 | 26-1 | 23-8 | 22-4 | 20-9 | 26-1 | 23-8 | 22-4 | 20-9 (1) |
| L/480 · 14 in · TJI 110 | 22-10 | 20-11 | 19-2 | 17-2 (1) | 22-2 | 19-2 | 17-6 (1) | 15-0 (1) |
| L/480 · 14 in · TJI 210 | 23-11 | 21-10 | 20-8 | 18-10 (1) | 23-11 | 21-1 | 19-2 (1) | 16-7 (1) |
| L/480 · 14 in · TJI 230 | 24-8 | 22-6 | 21-2 | 19-9 (1) | 24-8 | 22-2 | 20-3 (1) | 17-6 (1) |
| L/480 · 14 in · TJI 360 | 26-0 | 23-8 | 22-4 | 20-9 (1) | 26-0 | 23-8 | 22-4 (1) | 17-10 (1) |
| L/480 · 14 in · TJI 560 | 29-6 | 26-10 | 25-4 | 23-6 | 29-6 | 26-10 | 25-4 (1) | 20-11 (1) |
| L/480 · 16 in · TJI 110 | 25-4 | 22-6 | 20-7 (1) | 18-1 (1) | 23-9 | 20-7 (1) | 18-9 (1) | 15-0 (1) |
| L/480 · 16 in · TJI 210 | 26-6 | 24-3 | 22-6 (1) | 19-11 (1) | 26-0 | 22-6 (1) | 20-7 (1) | 16-7 (1) |
| L/480 · 16 in · TJI 230 | 27-3 | 24-10 | 23-6 | 21-1 (1) | 27-3 | 23-9 | 21-8 (1) | 17-6 (1) |
| L/480 · 16 in · TJI 360 | 28-9 | 26-3 | 24-8 (1) | 21-5 (1) | 28-9 | 26-3 (1) | 22-4 (1) | 17-10 (1) |
| L/480 · 16 in · TJI 560 | 32-8 | 29-8 | 28-0 | 25-2 (1) | 32-8 | 29-8 | 26-3 (1) | 20-11 (1) |
| L/360 · 9 1/2 in · TJI 110 | 18-9 | 17-2 | 15-8 | 14-0 | 18-1 | 15-8 | 14-3 | 12-9 |
| L/360 · 9 1/2 in · TJI 210 | 19-8 | 18-0 | 17-0 | 15-4 | 19-8 | 17-2 | 15-8 | 14-0 |
| L/360 · 9 1/2 in · TJI 230 | 20-3 | 18-6 | 17-5 | 16-2 | 20-3 | 18-1 | 16-6 | 14-9 |
| L/360 · 11 7/8 in · TJI 110 | 22-3 | 19-4 | 17-8 | 15-9 (1) | 20-5 | 17-8 | 16-1 (1) | 14-4 (1) |
| L/360 · 11 7/8 in · TJI 210 | 23-4 | 21-2 | 19-4 | 17-3 (1) | 22-4 | 19-4 | 17-8 | 15-9 (1) |
| L/360 · 11 7/8 in · TJI 230 | 24-0 | 21-11 | 20-5 | 18-3 | 23-7 | 20-5 | 18-7 | 16-7 (1) |
| L/360 · 11 7/8 in · TJI 360 | 25-4 | 23-2 | 21-10 | 20-4 (1) | 25-4 | 23-2 | 21-10 (1) | 17-10 (1) |
| L/360 · 11 7/8 in · TJI 560 | 28-10 | 26-3 | 24-9 | 23-0 | 28-10 | 26-3 | 24-9 | 20-11 (1) |
| L/360 · 14 in · TJI 110 | 24-4 | 21-0 | 19-2 | 17-2 (1) | 22-2 | 19-2 | 17-6 (1) | 15-0 (1) |
| L/360 · 14 in · TJI 210 | 26-6 | 23-1 | 21-1 | 18-10 (1) | 24-4 | 21-1 | 19-2 (1) | 16-7 (1) |
| L/360 · 14 in · TJI 230 | 27-3 | 24-4 | 22-2 | 19-10 (1) | 25-8 | 22-2 | 20-3 (1) | 17-6 (1) |
| L/360 · 14 in · TJI 360 | 28-9 | 26-3 | 24-9 (1) | 21-5 (1) | 28-9 | 26-3 (1) | 22-4 (1) | 17-10 (1) |
| L/360 · 14 in · TJI 560 | 32-8 | 29-9 | 28-0 | 25-2 (1) | 32-8 | 29-9 | 26-3 (1) | 20-11 (1) |
| L/360 · 16 in · TJI 110 | 26-0 | 22-6 | 20-7 (1) | 18-1 (1) | 23-9 | 20-7 (1) | 18-9 (1) | 15-0 (1) |
| L/360 · 16 in · TJI 210 | 28-6 | 24-8 | 22-6 (1) | 19-11 (1) | 26-0 | 22-6 (1) | 20-7 (1) | 16-7 (1) |
| L/360 · 16 in · TJI 230 | 30-1 | 26-0 | 23-9 | 21-1 (1) | 27-5 | 23-9 | 21-8 (1) | 17-6 (1) |
| L/360 · 16 in · TJI 360 | 31-10 | 29-0 | 26-10 (1) | 21-5 (1) | 31-10 | 26-10 (1) | 22-4 (1) | 17-10 (1) |
| L/360 · 16 in · TJI 560 | 36-1 | 32-11 | 31-0 (1) | 25-2 (1) | 36-1 | 31-6 (1) | 26-3 (1) | 20-11 (1) |
Weyerhaeuser TJ-4000 (July 2025), Floor Span Tables, page 7, as printed: feet-inches (19-3 is 19 ft 3 in) of clear distance between supports, 40 psf live load, uniform loads, the more restrictive of simple or continuous span, with a glue-nailed 24 in on-center span-rated subfloor; without subfloor adhesive the spans are 6 in shorter with nails and 12 in shorter with proprietary fasteners. (1) Web stiffeners at the intermediate support of a continuous-span joist when that bearing is shorter than 5 1/4 in and the span on either side is past the threshold the guide prints under the table. The guide also prints some spans in bold italic, for an initial dead load deflection over 0.33 in; that mark is not reproduced here.
Where the numbers come from
- Spans: Weyerhaeuser Trus Joist TJI Joist Specifier's Guide TJ-4000, July 2025 edition, page 7, Floor Span Tables for 9 1/2 to 16 in TJI 110, 210, 230, 360 and 560 joists, printed in full below: L/480 and L/360 live load deflection, 40 psf live load with 10 or 20 psf dead load, at 12, 16, 19.2 and 24 in on center. Spans are the clear distance between supports, for uniform loads, the more restrictive of simple or continuous span, with a single layer of glue-nailed span-rated floor panels; without subfloor adhesive the guide takes 6 in off for nails and 12 in for proprietary fasteners. Joist weight per foot, page 6. Read October 31, 2026, and checked cell by cell against the PDF. TJ-4000 guide (PDF)
- Nothing is engineered here: the page reads the cell, takes off 6 or 12 in when there is no glue, and for a span you type lists every depth, series and spacing whose span is at least that long, ordered by pounds of joist per square foot of floor (weight per foot × 12 ÷ spacing).
These are Weyerhaeuser's spans for its own TJI joists. LP SolidStart, Boise Cascade BCI and other I-joists carry their makers' tables, which differ. The table covers uniform floor loads of 40 psf live; a point load from a post, a bearing wall or a hot tub is outside it. The 18 to 24 in TJI depths are in a separate table of the same guide, at 25 psf dead load.
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